Zika fight doesn’t diminish with change in Zika status

While many Americans were recovering from their holiday feasts last week, the Emergency Committee of the World Health Organization (WHO) was deliberating on whether Zika virus is still a Public Health Emergency of International Concern (PHEIC).[1] Although the decision was made to move Zika from PHEIC to endemic status,[2] this post aims to discuss why now is the time to focus more resources on Zika.

Zika is here to stay

Being labeled as an endemic virus makes one thing clear: Zika is not going anywhere. Over time, the hope is that many populations who have been introduced to the virus for the first time, such as in the Americas, will become immune. But a community cannot build immunity to Zika overnight. Rather, a given population will become protected gradually as the virus circulates throughout the area and individuals are infected. Once infected, a person will likely develop an immune response that provides protection against future infection.

Many U.S. states that provide a hospitable environment for the primary Zika-carrying culprit, the Aedes aegypti mosquito, have not yet seen outbreaks. This puts communities at risk of experiencing the negative effects of Zika, as the virus infects the population for the first time. For those of us who have not yet developed immunity, continuing vaccine research and development is essential to keeping the Zika endemic at bay.

Winter is the best time to get work done

North America is now entering colder months, where temperatures will likely be low enough (in most places) to keep mosquito populations at bay. The winter season essentially acts as Mother Nature’s contribution to mosquito abatement. Nonetheless, we cannot assume that mosquitoes are dead and gone—the eggs of the Aedes aegypti mosquito simply go dormant during colder months, but they do not die. When spring returns with warmer temperatures, surviving eggs need no more than a capful of water to complete their hatching process. Since Zika is transferred from the female mosquito to her eggs, we will see Zika-infected offspring if any Zika-infected mothers laid eggs. Still, while mosquito activity slows, winter is an ideal time for us to continue to eliminate breeding grounds through mosquito abatement and to plan for the resurgence of Zika at the start of the next mosquito season.

Not an easy fight

Unfortunately, there are a few confounding factors that make preparing for, fighting against, and responding to a Zika endemic more difficult:

(1) Although Zika-carrying mosquitoes go dormant in colder months, humans who live in or travel to/from Zika-affected areas can still spread Zika to each other sexually.

(2) Not all U.S. states will see cold enough temperatures for Zika-carrying mosquitoes to go dormant. Case in point: Texas, which identified its first case of local transmission days after the WHO changed the Zika status.[3]

(3) Even if the spread of Zika virus slows, there are still thousands of people worldwide who have already been impacted by Zika. If ongoing studies that track how the virus progresses in humans are stopped, we may miss clues as to how we can best prepare for the impacts of Zika.

We must stay vigilant

It is important to remember with Zika’s status change from PHEIC to endemic, the WHO is not giving any of us (public health experts, government stakeholders, nor community members) permission to turn our backs on those communities and individuals who are at risk of contracting Zika. We must continue public outreach, vaccine development, preparedness planning, and mosquito surveillance and abatement efforts while Zika-carrying mosquitos lay low and some stakeholders try to shift resources elsewhere.

And let’s keep a close eye on what develops in Latin America as their summer season returns. We may see some clues on what to expect when we exit our hibernation period next spring and face the Zika monster once again.